Due to its renewability and generally low cost, various attempts have been made to form fibers from starch. Conventionally, starch fibers have been produced using a wet-spinning process. For example, a starch/solvent colloidal suspension may be extruded from a spinneret into a coagulating bath. This process relied on the marked tendency of amylose to align and form strongly associated aggregates to provide strength and integrity to the final fiber. Any amylopectin present was tolerated as an impurity that adversely affected the fiber spinning process and the strength of the final product. Because it was well known that natural starch was rich in amylopectin, earlier approaches included pre-treating the natural starch to obtain the amylose-rich portion desirable for fiber spinning. However, this approach was not economically feasible on a commercial scale because a large portion (i.e., the amylopectin portion) of the starch was discarded. More recently, attempts have been made to melt spin starch into fibers. U.S. Pat. No. 6,890,872 to Bond, et al., for example, describes highly attenuated fibers produced by melt spinning a composition comprising destructurized starch, a biodegradable thermoplastic polymer, and a plasticizer. Unfortunately, however, such fibers are believed to possess inadequate strength and mechanical properties for use in many applications.
As such, a need currently exists for starch fibers that exhibit good mechanical properties.